My dad would answer thus ... Well actually it's a good thing. God is letting it happen to fulfill Bible prophecy and to wake people up. Turn to Matt. 24 and notice that earthquakes are just another sign the end is closer than you think. Jehovah is showing his loving kindness by allowing these warnings so people will take notice. They need to begin serving him or they will be destroyed.
My parents as well as other J.W's I know get extremely excited when there is a disaster like this that fits into prophecy.